JS_window.onload

var loadhandler = function(fun){
    if(typeof fun !== "function") return false;
    if(!!window.onload){
        var oldfun = window.onload;
        window.onload = function(){
            oldfun();
            fun();
            }
        }else{
        window.onload = fun;
        }
    }
var inputhandler = function(node,fun){
    if("oninput" in node){
        node.oninput = fun;
        }else{
        node.onpropertychange = fun;
        }
    }

//inputhandler实例

<input type="text" name="text" id="text" />
<input type="text" name="text" />
<input type="text" name="text" />
<div id="main"></div>

var text = document.getElementsByName("text");
for(var i=0,j=text.length;i<j;i++){
    inputhander(text[i],function(){
        var value = 0;
        for(var ini=0;ini<j;ini++){
            value += +text[ini].value;
            }
        document.getElementById("main").innerHTML = value;
        });